The present invention relates to a seal system for use in a rotary engine having partitions or apex seals held in sliding contact with the inner surface of a rotor housing.
Rotary engines known widely as Wankel engines have a seal system including apex seals slidable against the inner wall surface of a rotor housing. Since the apex seals are held in substantial point-to-point contact with the rotor housing inner surface, they fail to provide a sufficient degree of airtight seal and are difficult to maintain an oil film on the rotor housing inner surface, requiring a large amount of lubricating oil to be supplied to the housing surface for preventing seizure. With such a lubricating requirement, an increased quantity of lubricating oil is scraped off the rotor housing by the apex seals and discharged through an exhaust port. The rotor housing wall surface needs to be coated with a hard plated layer of chromium to avoid chatter marks which would otherwise be formed on the rotor housing wall surface. There have been proposed no rotary engines employing sliding plates as seals. Such rotary engines would be widely different in construction from the Wankel engine, and would require a seal system of a substantially totally new arrangement.
The seals are pressed against the inner surface of the rotor housing under resilient forces acting on the rear surfaces of the seals from a gas introduced under pressure in spaces defined in the rotor behind the seals. The gas pressure on the rear surfaces of the seals is offset by a gas pressure acting on the sealing surfaces of the seals. Therefore, the sealing effect attained by such seals is achieved only by a weak force tending to press the seals against the rotor housing surface dependent on the gas pressure applied.